The latest news in autism and genetics, courtesy of Laura Blue writing at Time Healthland:
In one of the largest-ever studies of genetics and autism, researchers have identified 24 new gene variants associated with autism spectrum disorders (ASD). The work also confirms that 31 variants previously linked to the developmental disorder may serve as useful genetic markers for identifying those with the condition.
The keyword for this study, one that doesn’t appear in most news stories about it, is copy number variation, or CNV. The study authors, hailing from Children’s Hospital of Philadelphia, investigated rare CNVs occurring with high frequency in families that had a high representation of autistic people. Writing in their introduction that as many as 400 genes or chromosomal regions might be involved in autism risk, the authors, led by senior author Hakon Hakonarson, go on to describe their results: identification of “multiple rare recurrent CNVs” from high-risk families.
But what is a CNV? In general terms, a change in your genome sequence can mean a small alteration, like removing or adding a single link in a chain, or it can mean a structural change involving bigger chunks, like removing or adding whole sections of the chain. An example of a chunky structural change is a duplication or deletion of a longish DNA sequence. The result is variation in the number of copies of that sequence, a variability we call CNV. Having more or less than the typical number of copies could be meaningless or meaningful to an organism, depending on what the effects of a specific number are.
With autism, some of these variants seem to matter. This latest research discusses CNVs that are high impact, rare number variants with pretty big effects in terms of autism risk. Big effects can translate into big tests: If a specific number variant is linked to sufficiently high possibility of autism, that variant could serve as an identifiable marker for the condition. According to the paper authors, such markers could help identify autism risk early enough for effective behavioral intervention. Of course, “risk” doesn’t mean “has it.” And even though some variants the team identified lie near genes associated with brain proteins, much work remains before anyone traces a clear path from a particular CNV or suite of CNVs through all of the molecular milestones that lead to what we call autism.
View the full post here: Autism And Genetics: It’s Complicated